thats my point. Antifa as a whole would never allie with "facists" but at the same time a sizeable portion of their members would probably be willing to walk away and allie with facists if nessary if they have a more pressing matter to attend to.

Well if their was a serious effort to abolish the system that for some reason needed an alliance between far left and far right groups, there is a good chance a lot of members of each group that opposes each other would weigh the risks and benifits and possibly decide to ditch their diffrences (for now) to accomplish one goal. So sure antifia would still "exist" in this hypthetical situation, but lots of people who would normally march with them would be preoccupied with the more pressing matter of overthrowing the main power.